/*******************************************************************************
 * Copyright (c) 2014, 2015 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Ian Craggs - initial API and implementation and/or initial documentation
 *    Nicholas Humfrey - Reformatting to make more consistent; bug 453862
 *******************************************************************************/

#include "MQTTSNPacket.h"
#include "StackTrace.h"

#include <string.h>


/**
  * Determines the length of the MQTT connect packet that would be produced using the supplied connect options.
  * @param options the options to be used to build the connect packet
  * @return the length of buffer needed to contain the serialized version of the packet
  */
int MQTTSNSerialize_connectLength(MQTTSNPacket_connectData* options)
{
    int len = 0;

    FUNC_ENTRY;
    len = 5 + MQTTSNstrlen(options->clientID);
    FUNC_EXIT_RC(len);
    return len;
}


/**
  * Serializes the connect options into the buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffer
  * @param options the options to be used to build the connect packet
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_connect(unsigned char* buf, int buflen, MQTTSNPacket_connectData* options)
{
    unsigned char *ptr = buf;
    MQTTSNFlags flags;
    int len = 0;
    int rc = -1;

    FUNC_ENTRY;
    if ((len = MQTTSNPacket_len(MQTTSNSerialize_connectLength(options))) > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    ptr += MQTTSNPacket_encode(ptr, len); /* write length */
    writeMQTTSNChar(&ptr, MQTTSN_CONNECT);      /* write message type */

    flags.all = 0;
    flags.bits.cleanSession = options->cleansession;
    flags.bits.will = options->willFlag;
    writeMQTTSNChar(&ptr, flags.all);
    writeMQTTSNChar(&ptr, 0x01);                 /* protocol ID */
    writeMQTTSNInt(&ptr, options->duration);
    writeMQTTSNString(&ptr, options->clientID);

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Deserializes the supplied (wire) buffer into connack data - return code
  * @param connack_rc returned integer value of the connack return code
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_connack(int* connack_rc, unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen;

    FUNC_ENTRY;
    curdata += (rc = MQTTSNPacket_decode(curdata, buflen, &mylen)); /* read length */
    enddata = buf + mylen;
    if (enddata - buf < 3)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_CONNACK)
        goto exit;

    *connack_rc = readMQTTSNChar(&curdata);

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Determines the length of the MQTT disconnect packet (without length field)
  * @param duration the parameter used for the disconnect
  * @return the length of buffer needed to contain the serialized version of the packet
  */
int MQTTSNSerialize_disconnectLength(int duration)
{
    int len = 0;

    FUNC_ENTRY;
    len = (duration > 0) ? 3 : 1;
    FUNC_EXIT_RC(len);
    return len;
}


/**
  * Serializes a disconnect packet into the supplied buffer, ready for writing to a socket
  * @param buf the buffer into which the packet will be serialized
  * @param buflen the length in bytes of the supplied buffer, to avoid overruns
  * @param duration optional duration, not added to packet if < 0
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_disconnect(unsigned char* buf, int buflen, int duration)
{
    int rc = -1;
    unsigned char *ptr = buf;
    int len = 0;

    FUNC_ENTRY;
    if ((len = MQTTSNPacket_len(MQTTSNSerialize_disconnectLength(duration))) > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    ptr += MQTTSNPacket_encode(ptr, len); /* write length */
    writeMQTTSNChar(&ptr, MQTTSN_DISCONNECT);      /* write message type */

    if (duration > 0)
        writeMQTTSNInt(&ptr, duration);

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Serializes a disconnect packet into the supplied buffer, ready for writing to a socket
  * @param buf the buffer into which the packet will be serialized
  * @param buflen the length in bytes of the supplied buffer, to avoid overruns
  * @param clientid optional string, not added to packet string == NULL
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_pingreq(unsigned char* buf, int buflen, MQTTSNString clientid)
{
    int rc = -1;
    unsigned char *ptr = buf;
    int len = 0;

    FUNC_ENTRY;
    if ((len = MQTTSNPacket_len(MQTTSNstrlen(clientid) + 1)) > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    ptr += MQTTSNPacket_encode(ptr, len); /* write length */
    writeMQTTSNChar(&ptr, MQTTSN_PINGREQ);      /* write message type */

    writeMQTTSNString(&ptr, clientid);

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Deserializes the supplied (wire) buffer
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_pingresp(unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen;

    FUNC_ENTRY;
    curdata += MQTTSNPacket_decode(curdata, buflen, &mylen); /* read length */
    enddata = buf + mylen;
    if (enddata - curdata < 1)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_PINGRESP)
        goto exit;

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Serializes a willtopic or willtopicupd packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffer
  * @param willQoS the qos of the will message
  * @param willRetain the retained flag of the will message
  * @param willTopic the topic of the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willtopic1(unsigned char* buf, int buflen, int willQoS, unsigned char willRetain, MQTTSNString willTopic,
        enum MQTTSN_msgTypes packet_type)
{
    unsigned char *ptr = buf;
    MQTTSNFlags flags;
    int len = 0;
    int rc = -1;

    FUNC_ENTRY;
    if ((len = MQTTSNPacket_len(MQTTSNstrlen(willTopic) + 2)) > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    ptr += MQTTSNPacket_encode(ptr, len); /* write length */
    writeMQTTSNChar(&ptr, packet_type);      /* write message type */

    flags.all = 0;
    flags.bits.QoS = willQoS;
    flags.bits.retain = willRetain;
    writeMQTTSNChar(&ptr, flags.all);

    writeMQTTSNString(&ptr, willTopic);

    rc = ptr - buf;

exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Serializes a willtopicupd packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffer
  * @param willQoS the qos of the will message
  * @param willRetain the retained flag of the will message
  * @param willTopic the topic of the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willtopicupd(unsigned char* buf, int buflen, int willQoS, unsigned char willRetain, MQTTSNString willTopic)
{
    return MQTTSNSerialize_willtopic1(buf, buflen, willQoS, willRetain, willTopic, MQTTSN_WILLTOPICUPD);
}


/**
  * Serializes a willtopic packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffer
  * @param willQoS the qos of the will message
  * @param willRetain the retained flag of the will message
  * @param willTopic the topic of the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willtopic(unsigned char* buf, int buflen, int willQoS, unsigned char willRetain, MQTTSNString willTopic)
{
    return MQTTSNSerialize_willtopic1(buf, buflen, willQoS, willRetain, willTopic, MQTTSN_WILLTOPIC);
}


/**
  * Serializes a willmsg or willmsgupd packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param buflen the length in bytes of the supplied buffer
  * @param willMsg the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willmsg1(unsigned char* buf, int buflen, MQTTSNString willMsg, enum MQTTSN_msgTypes packet_type)
{
    unsigned char *ptr = buf;
    int len = 0;
    int rc = -1;

    FUNC_ENTRY;
    if ((len = MQTTSNPacket_len(MQTTSNstrlen(willMsg) + 1)) > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    ptr += MQTTSNPacket_encode(ptr, len); /* write length */
    writeMQTTSNChar(&ptr, packet_type);      /* write message type */

    writeMQTTSNString(&ptr, willMsg);

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Serializes a willmsg packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffersage
  * @param willMsg the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willmsg(unsigned char* buf, int buflen, MQTTSNString willMsg)
{
    return MQTTSNSerialize_willmsg1(buf, buflen, willMsg, MQTTSN_WILLMSG);
}


/**
  * Serializes a willmsgupd packet into the supplied buffer.
  * @param buf the buffer into which the packet will be serialized
  * @param len the length in bytes of the supplied buffersage
  * @param willMsg the will message
  * @return serialized length, or error if 0
  */
int MQTTSNSerialize_willmsgupd(unsigned char* buf, int buflen, MQTTSNString willMsg)
{
    return MQTTSNSerialize_willmsg1(buf, buflen, willMsg, MQTTSN_WILLMSGUPD);
}


/**
  * Deserializes the supplied (wire) buffer
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_willtopicreq(unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = -1;
    int mylen;

    FUNC_ENTRY;
    if (MQTTSNPacket_decode(curdata++, buflen, &mylen) != 1) /* read length */
        goto exit;
    if (mylen > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    enddata = buf + mylen;
    if (enddata - curdata < 1)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_WILLTOPICREQ)
        goto exit;

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Deserializes the supplied (wire) buffer
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_willmsgreq(unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = -1;
    int mylen;

    FUNC_ENTRY;
    if (MQTTSNPacket_decode(curdata++, buflen, &mylen) != 1) /* read length */
        goto exit;
    if (mylen > buflen)
    {
        rc = MQTTSNPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    enddata = buf + mylen;
    if (enddata - curdata < 1)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_WILLMSGREQ)
        goto exit;

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Deserializes the supplied (wire) buffer into willtopicresp data - return code
  * @param connack_rc returned integer value of the return code
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_willtopicresp(int* resp_rc, unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen;

    FUNC_ENTRY;
    curdata += MQTTSNPacket_decode(curdata, buflen, &mylen); /* read length */
    enddata = buf + mylen;
    if (enddata - buf < 3)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_WILLTOPICRESP)
        goto exit;

    *resp_rc = readMQTTSNChar(&curdata);

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
  * Deserializes the supplied (wire) buffer into willmsgresp data - return code
  * @param connack_rc returned integer value of the return code
  * @param buf the raw buffer data, of the correct length determined by the remaining length field
  * @param len the length in bytes of the data in the supplied buffer
  * @return error code.  1 is success, 0 is failure
  */
int MQTTSNDeserialize_willmsgresp(int* resp_rc, unsigned char* buf, int buflen)
{
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen;

    FUNC_ENTRY;
    curdata += MQTTSNPacket_decode(curdata, buflen, &mylen); /* read length */
    enddata = buf + mylen;
    if (enddata - buf < 3)
        goto exit;

    if (readMQTTSNChar(&curdata) != MQTTSN_WILLMSGRESP)
        goto exit;

    *resp_rc = readMQTTSNChar(&curdata);

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}
